(1) Field of the Invention
This device relates to band clamps to clamp or couple, together, two tubes, pipes or shafts, end to end, using the principle of toggle lever, to draw the band tight over the tubes, pipes or shafts. This invention provides an improved tightening mechanism utilizing the toggle lever type and also satisfying the sanitation requirement in the food industry.
Connectors utilizing the toggle lever action together with toggle linkage connecting the terminals of a band clamp, have been utilized and proposed in many different forms. However, toggle connectors by their nature embody problems of manufacture and design. The present invention is relatively simple, easy to manufacture and inexpensive. It also satisfies the rigid sanitation requirements in today's strict regulation of sanitation in the pharmaceutical, food, and flour milling industries. Also it is the only clamp of toggle type that provides mechanically balanced quick coupling for rotating shafts, without the problem of vibration or resonance. In addition, this clamp has uniform force distributed along its total width, and this clamping force can easily be increased by using wider clamps. This feature also distinguishes this invention from all other clamps using the toggle action and broadens the field of application using this invention. The wider the clamp band the higher is the clamping force and the higher is the reliability.
Moreover, many of the other clamps of many different designs are not suitable in the food processing, especially in flour mills, because the flour and dust enter into the spaces between the clamp parts and infestation takes place, causing sanitary problems. This invention has a streamlined shape and less voids inside its parts. It is easy to clean by wiping or brushing. This invention is secured against sudden opening by a wing nut, which is another important merit for reliability and prevention of accidents due to the pipes or shafts becoming loose and hitting someone or causing damage.
This invention consists of simple pieces easy to manufacture in mass production and is inexpensive compared to other clamps. It does not rely on screws, bails or holes to wear. This clamp can be used over and over again.
Sometimes, in practice, in pneumatic conveying systems, the conveying tubes, at their meeting ends, are connected by welding, because conventional clamps are not strong and suitable. In the flour mills or grain elevators systems, welding is dangerous because of the grain dust, and in many cases explosions took place. This invention provides an alternative way to connect instead of welding especially when a rubber gasket and a strengthening sleeve are used with the clamp as in FIG. 1A and 3B, with modern adhesive applied to the inner surface of the rubber sleeve. This invention also eliminates the need to flange the ends of the two tubes and so eliminates the higher costs of flanging the end of the conveying tubes. This invention is the most economical clamping or coupling device in the modern technology.
(2) Descriptions of the Prior Arts
All conventional toggle type clamps are limited in width and rely in their linkages on bails, hooks, holes into which the link pivots. These linking methods are weak and so the strength of such clamps is limited. Also the conventional clamps of toggle type are not sanitary because they have big voids inside where food, flour particles, and dust accumulate and cause infestation problems. These conventional toggle type clamps are complicated and expensive to manufacture. It is worthy to mention that my invention is very economical, sanitary and with unlimited width and corrugated band, can not only connect tubes but also support the joint against deflection when the tubes are inclined to the vertical, eliminating other expensive supports for conveying lines.
British Pat. No. 845537 is of V shape suitable only to connect flanged tubes.
U.S. Pat. No. 2846244 is also of V shape suitable only to connect flanged tubes.
Belgian Pat. No. 625822 is also of V shape.
British Pat. No. 208977 is limited in width and uses holes for pivoting and its strength depends on its axis of rotation strength.
As mentioned before, all conventional toggle clamp types are limited in width, have weak links and parts wear quickly and are not sanitary. They are expensive to make and cannot be used over and over again when compared to my invention which covers wide applications economically.